Supercritical fluid CO<Subscript>2</Subscript>-extraction regeneration of nickel–molybdenum catalyst for hydrotreatment

Results from studying the supercritical fluid СО₂-extraction regeneration of DN-3531 industrial nickel–molybdenum hydrotreatment catalyst in the temperature range of 323.15–383.15 K, at pressures of up to 30 MPa, and with modification of the basic extragent with such polar compounds as chloroform, methanol, ethanol, acetone, and dimethylsulfoxide (DMSO), are presented. The order of modifiers corresponds to the increase in the solubilizing ability of modified supercritical carbon dioxide (SC-СО₂) with respect to catalyst- deactivating deposits. With DMSO as the most efficient modifier, however, not only are deactivating compounds removed but nickel and molybdenum as well, considerably reducing the final activity of a regenerated sample. During extraction regeneration, the content of coke in the catalyst is reduced by two-thirds, while the specific surface area and the pore volume grow. The activity of the deactivated catalyst in dibenzothiophene hydrodesulfurization (HDS) and naphthalene hydrogenation grows by several hundred per cent after one-time SC-CO₂ treatment and is 2.5 times higher than for a sample regenerated using the traditional oxidative method.     

Producing Polydicyclopentadiene from Lower-Grade Dicyclopentadiene

Russian Engineering Research - Polymer samples based on polydicyclopentadiene produced from Russian dicyclopentadiene are investigated by thermogravimetric analysis and differential scanning...     

Impregnation of carbonate rock by deasphalted oil with the use of a supercritical fluid impregnation process

The authors present the results of investigation and experimental implementation of several processes: production of heavy oil residue and its deasphaltizing and impregnation of carbonate rock with deasphalted oil. Heavy oil residue has been produced during fractionation of highly-vicious oil by steam-thermal method. Deasphaltizing of oil-residue and impregnation of carbonate rock are implemented with the use of extraction and supercritical fluid impregnation processes with propane-butane solvent.     

Calculating values of kIII in a bimetal with an interphase crack

Translated from Fiziko-khimicheskaya Mekhanika Materialov, Vol. 27, No. 1, pp. 70–71, January–February, 1991.     

Echography in congenital intestinal obstruction in newborn infants

The authors used echography in order to reveal typical echographic signs of high and low bowel obstruction in 51 newborns. Although the use of echography often fails to establish the real cause of the bowel obstruction, it allows the determination of its level and in general promotes making the proper diagnosis.     

Extraction of hydrocarbons from oil emulsions with the use of a supercritical fluid extraction process with propane-butane extractant

Current paper represents the results of the study on extraction of hydrocarbons from oil emulsions using liquid and supercritical extraction processes. High-viscosity oil from Ashalchinskoye accumulation has been taken as a base for the emulsions with subsequent addition of water (0.5–30% wt.). A mixture of propane and butane has been applied as an extractant. The investigations have been carried out at temperatures 85–140?°C and pressures 10–15?MPa. The achieved output of light hydrocarbons is 93% of the total mass of hydrocarbons in emulsion. In parallel with the extraction, deasphaltizing has also been carried out.     

Numerical Simulation of Adsorption Equilibria of Gases on Microporous Active Carbons

Protection of Metals and Physical Chemistry of Surfaces - It has been demonstrated that adsorption isotherms on microporous activated carbons calculated by the method of molecular dynamics at...     

Mathematical Simulation of the Kinetics of Supercritical Fluid-Extraction Regeneration of a Heterogeneous Catalyst

A mathematical model that describes the kinetics of the extractional regeneration of a heterogeneous catalyst by a solvent, including that in its supercritical state, has been proposed. A comparison of the results of numerical and real experiments reveals their qualitative compliance over the entire time range of the process, as well as the quantitative agreement between them within the time range that corresponds to the high saturation of the catalyst with deactivating compounds.